Sprocket drive wheel



SePt- 21 1954 J. B. SILVER ErAL 2,689,891

sPEocxET DRIVE WHEEL Eiled June 21, 195o 2 sheets-sheet 1 lil IN VENTOR5 JOSfP/l 6. 7l Vfl? A 7' 7' ORA/IKS SePt- 21 1954 J. B. SILVER ETAL2,689,891A

SPROCKET DRIVE WHEEL Filed June 21, 195o 2 sheets-sheet 2 ATTORNEYSPatented Sept. 21,n 1954 UNITED STATES PATENT OFFICE SPROCKET DRIVEWHEEL Application June 21, 1950, Serial No. 169,482

Claims.

This invention relates to a sprocket drive wheel.

In connection with continuous conveyors, particularly of the chain;drive type, it is usual to have a power wheel provided with sprockets atits periphery to engage the drive chain and to provide the powermotivation for the conveyor.

With any type of conveyor the possibility of overloading or of jammingsometimes arises and it is necessary to have some type of device forrelieving the strain on the conveyor when this situation arises. Aclutch operation has been used and also a shear pin type of connectionbetween the drive shaft and the sprocket. However, with this type ofcontrol the power motor continues to operate and there is a loss ofpower as well as the wear on the clutch. Also, replacement of the shearpin is a time consuming operation.

In other devices it has been the practice to mount the drive sprocket ina oating frame and associate therewith a limit switch which would beactuated if an overload on the chain caused a shifting of the floatingframe.

The present invention contemplates a compound sprocket drive Wheel inwhich the power unit is associated with the sprocket in a resilientmanner and in which an overload on the chain being driven by thesprocket will be transferred as relative rotative movement between thesprocket wheel and the power unit. This relative movement will actuate aswitch to cut out the power motivation until the overload condition iscorrected. Y I

Briey, the invention consists oftwo co-axial plates, one of which is`associated with the motor and the other of which is associated with thechain. These plates are resiliently connected for mutual rotation andrelative rotation. A load on the conveyor chain will cause this relativerotation, and a switch actuating member mounted on both plates will beshifted by this relative rotation to actuate a limit switch.

There are additional advantages to the construction apart from the limitswitch operation. In many conveyors the installations cover aconsiderable distance, and it is necessary to have more than one powerdrive sprocket. When there are a plurality of drive sprockets, the powerunits are synchronized so that they will operate simultaneously.

The resilient connection in the drive member will smooth out variationsin the electrical signal synchronization and will also absorb theinitial shock of starting when the conveyor is long or loaded at thetime of the starting.

(Cl. G-51.46)

Other objects and features of the invention, including details ofconstruction and operation, will be apparent in the followingdescription and claims.

Drawings accompany the specification, and the various views thereof maybe briefly described as:

Figure l, a sectional view of the sprocket drive wheel taken on lineI--l of Figure 2.

Figure 2, a plan view of the drive wheel taken on line 2-2 of Figure 1.

Figure 3, a sectional View of the resilient connection between theco-axial plates taken on line 3-3 of Figure 2.

Figure 4, a side elevation on line 4-4 of Figure l showing the switchactuating member,

In the drawings, a mounting beam I0 has a bearing member I2 in which isjournaled a drive shaft I 4. This drive shaft is connected to a gear I6driven by a gear I8 from motor 20. Motor 2li is electrically driven andnormally operated by a switch 22. In the circuit of switch 22 is a limitswitch 24 actuated by a plunger 26 to open the circuit of the motor 20upon actuation as will be later described. The switch 24 is the typewhich requires a re-set before it will again close the circuit.

A drive sprocket ,plate has a hub 32 which is mounted for free rotationon a bushing 34 surrounding shaft I4. At the bottom of shaft I Il andco-axial with plate 3l) is an actuator or drive plate having a hub 42which is keyed to the shaftby key 44.

Plate 40 has a plurality of' projections de, di; and at corners of thetriangularly shaped plate. Each of these projections 45, 48 and 56 has asurface 52 on a plane which passes through the axis of the assembly anda radius of the sprocket plate.

On thus surface is mounted an Lshaped lug having one leg 54 projectingnormal tothe plate 4l) and another leg 56 projecting parallel to theplate 40 and in the same plane as the plate 3d. The leg 52 is reinforcedto the plate 40 fby triangular pieces 58.

The plate 36 has three dog leg shaped openings @il lying above theprojections 46, 48 and 50 of the actuator plate 40. The L-shaped lugs5ft-56 mounted on the actuating plate 40 extend into one end of theseopenings 60. At the other end of these openings is pivoted a clevis 62on a pin $4, the clevis having a stud projection 65.

A similar clevis 68 having a stud projection IU is pivoted on the lugleg 56 by a pin 12. Bolts 66 and. 'I0 on the respective clevises 52 and$8 serve as positioners for a relatively heavy spring 90. Due

3 to the L shape of the lugs 54-56 the bolts 66 and are in alignmentwithin the dog leg opening 60 of plate 30.

It will thus be seen that there is a resilient connection between theplates 30 and 40 wherein power applied to shaft I4 will be transmittedto the plate 30 through the springs 80.

As shown best in Figure 1 a lever 90 is disposed radially of the platesand pivoted at its outer end by a pin 92 to a block 94 fastened to plate30 outside the plate 40. Spaced radially from the pin 92 is a second pin96 which pivotally connects the lever 90 to plate I0. A free end 99 onthe lever 90 extends down below the shaft I4 to a point centrallythereof and mounted on the free end 98 is a cam |00. Normally this cam|00 is positioned relative to plunger 26 on limit switch 24 as shown inthe full lines of Figure 4. However, a relative rotating movementbetween plates 30 and 40 will cause the lever 90 to shift to the dottedline position of Figure 4, thus depressing the plunger 26 and actuatingthe limit switch to stop the motor 20. 'I'he limit switch is supportedindependently of the sprocket assembly by a means not shown.

In the operation of the device the starting of motor will actuate achain C engaging sprockets of plate 30. The springs 90 will absorb theinitial starting shock and the chain with whatever load it may becarrying will be actuated. If however, there is an overloading on thechain for any reason, the springs 80 will compress under the load,causing relative rotating movement between plates 30 and 40 and ashifting of the lever 90 and the cam |00 to depress the plunger of thelimit switch, thus stopping the system until switch 24 is re-set andenabling the operator to determine the cause of the overload.

What we claim is:

l. In a drive mechanism of the type having two adjacent co-axial driveplates resiliently linked together for relative and mutual rotativemovement and a control means for the plates, the combination of a meansfor actuating the control means comprising a lever pivotally mounted oneach of said plates at radially spaced points and through pivots havingaxes substantially parallel to the axis of said plates, said leverhaving a free end extending centerward in spaced relation to said platesin a position to operably associate with the control means, the free endof said lever being shiftable in a plane substantially parallel to theplane of said plates upon relative motion between said drive plates toactuate said control means.

2. In a drive mechanism of the type comprising two adjacent co-axialdrive plates resiliently linked together for relative and mutualrotative movement, a control means for said plates positioned concentrictherewith and spaced from said plates, the combination of an actuationfor said control means comprising an elongate bar pivotally mounted onand adapted to revolve with the plates, said bar having a free endextending to the center of said plates, means on the free end of saidbar to actuate said control means when shifted away from center, thefree end of said bar being shiftable away from center upon relativerotation of said plates while the plates are revolving.

3. A drive wheel mechanism comprising a wheel plate having a peripheralformation to engage a continuous chain or belt, means mounting saidplate for free rotation, a drive shaft, a drive plate mounted on saidshaft concentric with said wheel plate in a plane parallel to but spacedfrom said wheel plate, resilient means connecting said plates at aplurality of spaced points whereby power rotation of said drive platewill be transmitted to said wheel plate through said resilient means, alimit switch and actuator mounted adjacent and co-axially with butindependent of said plates, and a lever pivotally mounted on both saidwheel plate and said drive plate to rotate with said plates and having afree end extending centerward over said shaft and limit switch actuator,and a cam formation on said free end away from said shaft positioned toshift off-center to contact said actuator upon relative rotary motionbetween said disc and plate.

4. A drive mechanism comprising co-axial plates resiliently connected totransmit torque from one to the other and adapted to have re1- ativerotative movement upon the application of a predetermined torque load, aradially eX- tending bar pivotally connected to said plates at radiallyspaced points and arranged to revolve with said plates, said bar beingshifted from its radial position across the center of said plates uponrelative rotation of said plates, and control means at the center ofsaid plates independent of said plates responsive to said shifting toaffect the motion of said plates.

5. A device as defined in claim 4 in which the bar has a free endextending to the center of said plates and spaced therefrom, a cam onsaid end transversely located, and the control means comprises a limitswitch mounted independently of said plates to be actuated by said camupon relative rotative movement between plates.

References Cited in the file of this patent UNITED STATES- PATENTSNumber Name Date 829,371 Darlington Aug. 2l, 1906 2,113,666 Suman Apr.12, 1938 2,536,319 Slack Jan. 2, 1951

